The present invention relates, in general, to switchgear cabinets, which comprise at least one switchboard having at least one base plate, on which electrical switching devices are arranged and electrically interconnected for transmitting and/or distributing electrical energy to at least one piece of equipment. In this regard, the invention particularly relates to a method for manufacturing such a switchgear cabinet.
In the previous method of constructing switchgear cabinets, many manual procedures are included, for example drilling the circuit board, affixing the electrical components, and connecting the individual electrical connectors of the components. These manual procedures are subject to error and have high costs. Furthermore, in broad areas, it is usual to manufacture and assemble a switchgear cabinet in an operation specialized for this purpose, and then to transport it to the place of use, pre-assembled to a great extent, where then, only the external assemblies or equipment, such as, for example, the motors to be controlled by the switchgear cabinet, are connected, as is the case, for example, for cranes such as construction cranes, harbor cranes or offshore cranes. This regularly causes high transport costs.
In this regard, such switchgear cabinets regularly comprise multiple switchboards, which are accommodated in a switchgear cabinet housing horizontally and/or upright. In this regard, a plurality of switching elements are regularly mounted on base plates, which elements are electrically connected or wired with one another in order to implement the circuit logic. In this regard, the said switching elements or devices can be of the most varied types, for example switches, buttons, display elements such as displays or indicator lights, measuring devices, input means such as touch screens, pushbuttons, toggle switches and the like. In particular, components of power electronics can also be provided as switching elements on the base plate, for example frequency inverters and the like. Fuses or test switches can also be part of the switchboard.
Such a switchgear cabinet therefore usually forms or comprises a low-voltage switching device combination in a corresponding empty housing, wherein the said switching device combination, in most cases, comprises both a control part in the form of an auxiliary circuit and a power part in the form of a main circuit, including the required monitoring such as fuses, for example. Therefore a switchgear cabinet contains both a combination of one or more low-voltage switching devices with related equipment for control, measurement, reporting, protection and regulation, with all internal electrical and mechanical connections and design parts.
In this regard, switchgear cabinets have the task of receiving electrical energy, during operation, from one or more suppliers, and of distributing this energy to other equipment by way of one or more cables or lines. In this regard, the aforementioned main circuit comprises all the conductive parts of a switching device combination in a circuit that is supposed to transmit electrical power, while the auxiliary circuit comprises all the conductive parts of a switching device combination in a circuit that is not the aforementioned main circuit and is not supposed to transmit any electrical power, for control, measurement, reporting, regulation, and data processing.
From the documents DE 89 02 022 U1, US 2015/0201499 A1, WO 2014/2009994 A2, and DE 10 2011 100 555 A1 it is known to manufacture electronic modules in the form of circuit boards by means of 3D printing and other coating measures, at least in part. In contrast to a switchgear cabinet, however, such circuit boards are merely electronic modules that serve for data processing and control, without electrical power being received by them and transmitted or distributed to corresponding consumers. Such electronic modules in the form of circuit boards were initially manufactured using analog technology, and this was then developed further, step by step, to digital technology and then microcontroller technology.
In contrast to switchgear cabinets, very much smaller voltage and power ranges occur in the case of such circuit boards and electronic modules. While in the case of circuit boards and similar electronic modules for data processing and control, topics such as contact safety, electric shock or electric arc accidents are almost irrelevant because of the small voltage and power ranges that prevail in the case of electronic modules, the same topics must almost always be considered in switchgear cabinet construction. Because of this fundamental difference between circuit boards and electronic modules for data processing and control, on the one hand, and switchgear cabinets for distributing and transmitting electrical energy to other operating elements, some of them with life-threatening voltages, the risk of shock, and electric arc accidents, on the other hand, special caution and safety measures are required for manufacturing switchgear cabinets, in order to counter the special hazards of a switchgear cabinet. In particular, individual low-voltage switching devices are installed and inserted separately, one after the other. Furthermore, special structuring of the internal structure, with separate installation plates and support rails, and a division into a main circuit and an auxiliary circuit were undertaken in order to take the aforementioned special hazards into account. However, this makes manufacturing complicated, with many parts, and causes fatigue for the switchgear cabinet assembler.